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Finding the Fourth Proportional to 656.78, 906.40 and 394.80

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Solution

The fourth proportional to 656.78, 906.40 and 394.80 is: 544.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    656.78 : 906.40 = 394.80 : x
  2. Step 2: Convert to fraction form
    656.78/906.40 = 394.80/x
  3. Step 3: Cross multiply
    656.78x = 906.40 × 394.80
  4. Step 4: Simplify right side
    656.78x = 357,846.72
  5. Step 5: Solve for x
    x = 357,846.72/656.78
  6. Step 6: Final answer
    x = 544.85

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.